Twilight Sparkle stared in aroused shock as her sheath bloated larger. It filled the space between her crotchboobs, and the purple pony's balls dropped heavier and larger than both of them. Her dick grew longer and longer, thickening as it grew, until her cocktip was nearly twice the size of her face. The stallionhood was as thick around as Twilight's own body, and a bead of pre appeared at its tip, the bead as big as Twilight's tongue. Pony fuckmusk poured off her huge shaft and into Applebloom's face, causing the foal's belly to bloat in rapid pregnancy.
Twilight stared, her body and mind both shocked by the sudden growth of her cock. Her horn lit up, and she cast a spell, the words coming out of her mouth without her even thinking them. "Become me, become ME!" she yelled.
Applebloom felt the magic invade her and force her to grow. Her yellow body turned purple and thickened larger. Her identity shrunk as a new Twilight Sparkle personality forced its way into her brain. Standing up, she looked Twilight in the eyes, her eyes. This Twilight had a long, thick cock and balls like watermelons. "Yes. I'm you," the copy said, and her cock spurted ropes of jizz onto Twilight's belly. Twilight felt her gut sag heavily with pregnant weight, her Twilight clones growing bigger in her womb.
Twilight's own cock throbbed, and she shot ropes of seed onto her own chest and belly. She gasped and moaned as the pleasure washed through her, her cock growing and pulsing as she came and came. Her identical copy suffered the same. She could see and feel her ass plumping larger, buttcheeks inflating with fat fuck-me-now fat and curves.
Applejack trotted in, seeing both hyper-futa Twilight Sparkles standing and cumming in Applebloom's former room. The stench of sex and cum began affect her, her fur slowly turning purple and her ass starting to grow.
Both Twilights grinned, their dicks still pulsing as they sprayed hot white semen all over their bodies. They both knew how this went.
"Become me, become me!" Both Twilights yelled, and pointed their glowing horns at Applejack.
Applejack was forced to grow, becoming an exact copy of her friend and sister Twilight. The third Twilight's dick spurted as she felt the knowledge of what was happening fill her mind. "We've gotta breed the town!" She declared, her fat balls wobbling.
"Yes!" said the other two. "We'll need lots of help, so let's find everyone we know and infect them!"
"Yeah, let's go!"
The three hyper-cocked futas galloped out, their massive balls bouncing and wobbling as they ran, their massive cocks smacking the wall and ceiling with each step. The trio ran out of the barn, and found Rainbow Dash sitting on the ground, rubbing her plump, plush rump. She was panting and blushing, her blue wings spread and twitching. The smell of sex wafted off her as she stared at the three Twilights.
The three Twilights looked back at Rainbow Dash, and they all knew what needed to happen. They had a town to fuck.
"Become me, become ME!" the three futa mares shouted, and their horns glowed, hitting the cyan mare with the power of transformation. Rainbow Dash was forced to change, and her body grew, turning purple. Her cock spurted as she was changed, and the knowledge of her role and purpose filled her mind. "Alright, let's get this show on the road, yee-haw!" Rainbow Dash shouted. She galloped into the sky, the three Twilights running behind her.